As the demand of energy is increased the oil and gas industry is continuously trying to develop innovative technologies which will be used to increase the production of oil and gas in future. Besides many enhanced oil recovery techniques are present, the sandstone acidizing has been significantly developed to contribute to the petroleum industry. In sandstone acidizing different acids and their combination are applied on the formation. This results in minimizing the near wellbore damage and improve the well productivity. In this project we have performed acidizing on the sandstone rock of Ranikot formation which is present in the Lower Indus Basin. Drilling machine with different drill bit sizes are used to obtain different core samples from the formation rock. We applied HCl and HF acid, and their combination on the sandstone rock. In this project we observed the sandstone acidizing mechanism with different acids and observed problems that occurs due to the application of different acids on the formation. The laboratory results shows that the acidizing perform well when we use the mud acid which is the combination of HCl and HF acid. In the case of HCl acidization, most of the sandstone rock samples completely dissolve in the acid recipe and lose the bulk volume. But in the case of HF acidizing the rock cannot dissolve in the solution but precipitation takes place.
Table of Contents
1.1 Sedimentary Basin in Pakistan
1.2 Lower Indus basin:
1.2.1 Source rock of lower Indus basin:
1.2.3 Reservoir rock of lower Indus basin:
1.2.4 Ranikot Formation:
1.2.4 Formation and their depth present in lower Indus basin:
1.2.5 Discoveries in Lower Indus Basin:
1.2.6 Formation and discoveries in Lower Goru Formation of Lower Indus Basin:
Chapter 02
Porosity and Permeability
2.1 RESERVOIR ROCK PROPERTIES
2.1.1 Permeability
2.2 PERMEABILITY DETERMINATION
2.2.1 Procedure
Chapter 3
Matrix Acidizing
3.1 Abstract:
3.2 Well Stimulation:
3.3 Minerals in Sandstone:
3.4 Sandstone acidizing:
3.4.1 Acidizing Mechanism
3.4.2 Precipitates formation during Acidization in Sandstone
3.4.3 Solution to avoid Precipitation:
3.5 Problem associated with acidizing:
Chapter 4
Experimental Setup
4.1 Drilling and Coring
4.1.1 Definition:
4.1.2 Drilling Machine
4.1.2.2 Column:
4.1.2.4 Worktable:
4.1.2.5 Drill head:
4.1.2.6 Spindle:
4.1.2.7 Chuck:
4.1.2.8 Gears:
4.1.2.9 Electric Motor:
4.1.2.10 Drill Bits:
4.1.2.11 Procedure:
4.2 Porosity Calculations:
4.2.1 Procedure to determine the porosity of core sample using helium porosimeter
4.3 Permeability Calculations
4.3.2 Measuring Permeability by using Gas Permeameter:
4.4 Acid Recipe:
4.4.1 Acidizing Procedure:
Chapter 5
Results and Conclusions:
5.1 Drilling and Coring Process
5.1.1 Observation and Calculation:
5.1.2 Comments:
5.1.3 Precautions:
5.2 Porosity calculation before Acidizing
5.2.1 Observation and Calculation
5.3 Acid Recipes
5.3.1 Acid recipe using HCl
5.3.2 Acid recipe using HF
5.3.3 Acid recipe using HCl and HF
5.4 Porosity Calculations after Acidization
5.4.1 Observation and Calculation
5.4.2 Pictorial view of acidized core
5.6 Acid Recipes for small diameter samples
5.6.1 Acid recipe using HCL and pictorial representation of acidized cores
5.6.2 Acid recipe using HF and pictorial representation of acidized cores
5.6.3 Acid recipe using HCl and HF and pictorial representation of acidized cores
CHAPTER 6
Conclusion
Objectives and Research Themes
This work explores effective sandstone acidizing techniques to improve permeability and porosity in reservoir formations, specifically focusing on core samples from the Ranikot formation in Pakistan's Lower Indus Basin, with the primary objective to maximize hydrocarbon production through optimized acid treatment.
- Analysis of Lower Indus Basin reservoir properties and suitability for acidization.
- Evaluation of matrix acidizing mechanisms using HCl, HF, and mud acid combinations.
- Experimental setup for precise coring and acid application on sandstone samples.
- Investigation of porosity and permeability improvements versus mineral precipitation risks.
- Development of optimal acid recipes to minimize rock damage and maximize flow potential.
Excerpt from the Book
Sandstone acidizing:
The primary goal of matrix acidization on sandstone is to remove or dissolve different particles present in sandstone specially the siliceous particles like clay, feldspar, and quartz because they obstruct hydrocarbon flow and diminish permeability near the wellbore. HF acid was widely used since 1935, on sandstone formations to repair formation damage and solve difficulties linked to production damage in sandstone and also solve difficulties linked to the drilling of sandstone. Initially, this acid's primary use was to clean the walls of pipes by removing the mud cake, now HF is used to solve a variety of issues, including the removal of particles mostly the siliceous particles and near wellbore damage. When treating sandstone formations with a tiny amount of calcium minerals, this acid proved to be quite effective. Because only the fluoride ion (F-) can react with silica and clay, the particles of sandstone formation like sand grains, feldspar, and clays show reaction with Hydrofluoric acid. Dowel came up with the notion of combining HCl and HF acids to prevent reaction products from precipitating in 1940. Smith and Hendrickson and Nasr-El-Din (1986) documented injecting mud acid (combination of HCl and HF acids) on the sandstone having a concentration of 12 percent HCl and 3 percent HF. Precipitation processes can occur as a result of fluid–mineral interactions, which can limit reservoir permeability. The reactions HCl and HF with carbonate, as well as the responses of HF with siliceous particles such as silicates particles, quartz particles, and feldspar particles, are the most critical concerns when the mud acid (combination of HCl and HF acids) show reaction with the formation for the purpose to remove or dissolve distinct minerals.
Summary of Chapters
Chapter 1: This chapter provides an overview of the regional geology of the Lower Indus Basin, detailing its sedimentary geography and the characteristics of major formation units like the Goru and Ranikot.
Chapter 2: An examination of reservoir rock quality, focusing on porosity and permeability as the fundamental physical attributes influencing liquid storage and flow potential.
Chapter 3: This section covers the theoretical framework of matrix acidizing, including stimulation techniques, mineral composition, and the chemical mechanisms and challenges associated with acid treatment.
Chapter 4: Details the experimental configuration, outlining the drilling, coring, and measurement procedures, including the use of gas permeameters and porosity testing equipment.
Chapter 5: Presents the experimental observations, calculations, and data logs from testing different acid recipes on Ranikot core samples, including pictorial results.
Chapter 6: The final chapter summarizes experimental findings, concluding on the efficacy of combined acid solutions for increasing porosity while balancing the risks of precipitation.
Keywords
Sandstone, Matrix Acidizing, Lower Indus Basin, Porosity, Permeability, Ranikot Formation, Mud Acid, Stimulations, Hydrocarbon Production, Reservoir Engineering, Core Analysis, Precipitation, Silica, Mineralogy, Sedimentary Basin.
Frequently Asked Questions
What is the primary focus of this research?
The work investigates the laboratory application of acid stimulation techniques on sandstone core samples to enhance porosity and permeability in oil and gas reservoirs.
Which geographical area is the research based on?
The study centers on the Lower Indus Basin in Pakistan, specifically analyzing sandstone rock samples from the Ranikot formation.
What is the main research objective?
The objective is to evaluate how different acid treatments (HCl, HF, and their combinations) improve reservoir properties while minimizing drawbacks like rock dissolution or unwanted precipitation.
What scientific methods were employed?
The study utilized standardized laboratory procedures, including core drilling, helium porosimetry for porosity, gas permeameters for permeability, and controlled chemical reaction tests.
What topics are covered in the main body?
The main sections cover geological background, reservoir physics (porosity/permeability), the mechanisms of sandstone acidization, experimental setup, and the analysis of results obtained from various acid recipes.
Which keywords define this work?
Core keywords include Sandstone, Matrix Acidizing, Porosity, Permeability, Lower Indus Basin, and Mud Acid.
Why can HCl concentration cause problems in sandstone?
The research notes that if HCl concentration exceeds 3%, sandstone samples tend to dissolve completely, leading to a loss of rock integrity despite an increase in porosity.
How does mud acid differ from single-acid treatments?
Mud acid (a combination of HCl and HF) is found to be more effective than single components, as it can create desirable fractures and channels that increase porosity significantly without the severe structural decay associated with high-concentration HCl.
- Arbeit zitieren
- Muhammad Awais (Autor:in), 2022, A Laboratory Application of Acid Stimulation Technique in Sandstone Rock Samples from Lower Indus Basin, München, GRIN Verlag, https://www.grin.com/document/1282264
